Determination of non-steroidal estrogens in breast milk,plasma, urine and hair by gas chromatography/mass spectrometry

It is suspected that all the natural estrogens occurring in the human body, as well as dietary and synthetic estrogens, diversely affect the endocrine system depending on their exposure patterns. More rapid, reliable and accurate measurements of these compounds in various biological matrices are thus becoming an important task. After solid-phase extraction using an Oasis HLB extraction cartridge, the estrogen concentrates were derivatized with a mixture of N-methyl-N-trifluorotrimethylsilylacetamide/ammonium iodide/dithioerythritol (1000:4:5, v/w/w) for analysis by gas chromatography/mass spectrometry in the selected ion-monitoring (SIM) mode. The qualitative identification of estrogens detected in SIM mode was further confirmed by tandem mass spectrometry using low-energy collision-induced dissociation (CID) mode. The method for the assay of the 20 estrogens was linear over the ranges of 1-1000 micro g/L for biological fluids and 1-200 micro g/kg for hair with high correlation coefficient (>0.99). The limits of quantitation (LOQ) ranged from 1.0-10 micro g/L (or micro g/kg) and the limit of detection ranged from 0.2-3 micro g/L (or micro g/kg). The average precision (% CV) and accuracy (% bias) of the method determined at the LOQ, low, and medium concentrations were in the ranges 2.6-9.2 and -4.1-7.7, respectively. The average extraction recovery of the estrogens from plasma and hair at the three concentration levels varied in the ranges 77-103% (1.9-14.3% CV) and 73-104% (3.1-14%), respectively. The distribution patterns of the estrogens were characteristic of each biosample. Five estrogens in the range 1.5-44.9 micro g/L were measured in breast milk, 8 estrogens in the range 3.5-322 micro g/L in plasma, 12 estrogens at 1.2-442 micro g/L in urine, and biochanin-A at 13.2-39.1 micro g/kg in hair. Because of its high sensitivity, good precision and specificity, the present method was found suitable for the trace analysis of dietary and synthetic estrogens in complex biosamples such as breast milk, plasma, urine and hair.     

A symmetric derivative of the trimetallic nitride endohedral metallofullerene, Sc3N@C80.

The reaction of Sc3N@C80 with 6,7-dimethoxyisochroman-3-one (13C labeled) provides the first functionalized derivative of the trimetallic nitride template (TNT) endohedral metallofullerene family. The reaction mixture is dominated by a single 13C labeled monoadduct product that was purified by HPLC. The 13C labeled monoadduct was characterized by 1H NMR, 13C NMR, and MALDI-TOF mass spectrometry. The proposed structure for this novel symmetric monoadduct is consistent with derivatization at the [5,6] ring juncture on the Sc3N@C80 cage.     

Radical Copolymerization of Fluoroalkyl Methacrylates with Methyl Methacrylate

Lauryl peroxide initiated radical copolymerization of 1,1,3-trihydroperfluoropropyl methacrylate and 1,1,5-trihydroperfluoroamyl methacrylate with methyl methacrylate was studied. The kinetic parameters of copolymerization for these systems were determined at low degrees of conversion. Optically transparent copolymers with glass transition points within 50–80°C were synthesized.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5, 2005, pp. 818–821.Original Russian Text Copyright © 2005 by Man’ko, Mel’nichenko, Bovkunenko, Shendrik, Fedoseeva, Goncharov.     

分形表面粗糙度与光散射关系的研究

用Weielstxass－Mandelbrot函数产生了一维的分形表面，在几何光学适用的范围内研究了这些表面的光散射特性．发现分形线数D越大，通常被认为越粗糙的表面，其光散射的角分布反而比D小的表面更集中．文章最后解释了这种现象的成因．     

基于多层电介质光栅光谱合成的光束质量

基于电介质光栅的光谱合成是实现高功率高光束质量激光的重要途径. 在电介质光栅的光谱合成系统中, 光栅色散效应是影响合成激光光束质量的重要因素. 本文推导了单光栅和双光栅光谱合成系统中由于光栅色散引起M²因子的变化公式; 详细讨论了这两种合成系统中单路激光线宽、单路激光光斑半径、相邻两路激光波长差、相邻两路激光间距以及光栅周期对光束质量的影响. 研究表明对于单光栅合成系统, 在合成过程中若保持光束质量M²因子的大小不变, 则单路激光带宽随光斑半径的增加而减小; 在双光栅光谱合成系统中, 在保持光束质量的前提下, 单路激光带宽可随光斑半径的增大而相应增加. 数值计算表明, 若要满足合成光束的光束质量M² ≤1.2的要求, 在单光栅系统中激光线宽需窄于亚纳米量级, 在双光栅系统中激光带宽可为亚纳米. 本文为高功率、高光束质量的光纤激光光谱合成系统的搭建提供了理论指导.     

铁和镧共掺杂纳米二氧化钛光催化剂的制备、表征及其光催化活性

以葡聚糖为模板,钛酸四正丁酯、硝酸铁和硝酸镧为前驱体采用模板法制备了一系列铁、镧单掺杂及共掺杂纳米TiO₂光催化剂. 利用SEM、XRD、BET比表面积测定和UV-Vis等技术对其形貌、晶体结构及表面结构、光吸收特性等进行了表征. 以甲基橙溶液的光催化降解为模型反应,考察了不同掺杂的样品在紫外和可见光下的光催化性能. TiO₂材料具有较大的比表面积(约150 m²/g),铁和镧共掺杂纳米TiO₂在可见光区域有较强的吸收,在紫外和可见光条件下较纯TiO₂和单掺杂TiO₂对甲基橙溶液具有更好的光催化降解效果,且铁和镧的掺杂量显著影响该材料的催化性能. 当铁掺杂量为0.5mol%、镧掺杂量为0.3mol%,在500 ℃焙烧2 h所得光催化材料的催化性能最佳,焙烧4 h即可使甲基橙的降解率达98.8%,且该复合材料有较高的循环回收利用率,重复使用4次仍可使甲基橙的降解率保持在88%以上.     

Entropic Inequalities for Two Coupled Superconducting Circuits

We discuss the known construction of two interacting superconducting circuits based on Josephson junctions, which can be precisely engineered and easily controlled. In particular, we use the parametric excitation of two circuits realized by an instant change of the qubit coupling to study entropic and information properties of the density matrix of a composite system. We obtain the density matrix from the initial thermal state and perform its analysis in the approximation of small perturbation parameter and sufficiently low temperature. We also check the subadditivity condition for this system both for the von Neumann entropy and deformed entropies and check the dependence of mutual information on the system temperature. Finally, we discuss the applicability of this approach to describe the two coupled superconducting qubits as harmonic oscillators with limited Hilbert space.     

Discretization of the Density Matrix as a Nonlinear Positive Map and Entanglement

We propose the discretization of the density matrix as a nonlinear positive map for systems with continuous variables. We use this procedure for calculating the entanglement between two modes through different criteria, such as Tsallis entropy, von Neumann entropy and linear entropy, and the logarithmic negativity. As an example, we study the dynamics of entanglement for the two-mode squeezed-vacuum state in the parametric amplifier and show good agreement with the analytic results. Also we address the loss of information on the system state due to the discretization of the density matrix.     

On Multi‐component Ermakov Systems in a Two‐Layer Fluid: Integrable Hamiltonian Structures and Exact Vortex Solutions

By introducing an elliptic vortex ansatz, the 2+1‐dimensional two‐layer fluid system is reduced to a finite‐dimensional nonlinear dynamical system. Time‐modulated variables are then introduced and multicomponent Ermakov systems are isolated. The latter is shown to be also Hamiltonian, thereby admitting general solutions in terms of an elliptic integral representation. In particular, a subclass of vortex solutions is obtained and their behaviors are simulated. Such solutions have recently found applications in oceanic and atmospheric dynamics. Moreover, it is proved that the Hamiltonian system is equivalent to the stationary nonlinear cubic Schrödinger equations coupled with a Steen‐Ermakov‐Pinney equation.     

14‐Vertex Heteroboranes with 14 Skeletal Electron Pairs: An Experimental and Computational Study

Three isomers of [(Cp*Ru)₂C₂B₁₀H₁₂], the first examples of 14‐vertex heteroboranes containing 14‐skeletal electron pairs, have been synthesized by the direct electrophilic insertion of a {Cp*Ru⁺} fragment into the anion [4‐Cp*‐4,1,6‐RuC₂B₁₀H₁₂]^?. All three compounds have the same unique polyhedral structure having an approximate C_s symmetry and featuring a four‐atom trapezoidal face. X‐ray diffraction studies could confidently identify only one of the two cage C atoms in each structure. The other C atom position has been established by a combination of i) best fitting of computed and experimental ¹¹B and ¹H NMR chemical shifts, and ii) consideration of the lowest computed energy for series of isomers studied by DFT calculations. In all three isomers, one cage C atom occupies a degree‐4 vertex on the short parallel edge of the trapezium.